Secondary charge for compound detonators



Patented Apr. 14, 1%25.

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BENNETT GROTTA, 0F TAMAQUA, PENNSYLVANIA, ASSIGNOR TO ATLAS POWDER COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OF DELAWARE.

SECONDARY CHARGE COMPOUND DETONATORSL No Drawing.

To all whom it may concern: Be it known that BENNETT GROTTA, r. c1t1- zen of the United States, residing at Tamaqua, in the county of Schuylkill and State of Pennsylvania, has invented certalnnew and useful Improvements in Secondary Charges for Compound Detonators, of which the following is a specification.

My invention relates to improvements in that type of detonator commonly known as a compound detonator and relates particularly to.the main or secondary charge.

The history of modern commercial detonators dates back to the discovery that fulminate of mercury could be employed for initiating nitrogylcerine explosives. To this day fulminate of mercury has found universal application as a detcnator composition. Early in the development of modern explosives it was found that the efiiciency of fulminate of mercury could be in creased by the admixtures therewith of a certain class of compounds which, in themselves were not suited forinitiating purposes and which in some cases were not even explosive when used alone- These materials are rich in oxygen and are usually termed oxygen carriers. 7 Their admixture is usually so controlled as to supply the deficiency of oxygen in the fulminate of mercury molecule, 1. e., supply sufficient oxygen to enable all the carbon present to be converted into carbon dioxide and all the hydrogen present to be converted into water when the mixture is detonated. Various compounds have been used for accomplish-- ing this purpose, such as different metal oxides, perchlorates and chlorates, but of these the chlorate of postassium has probably been used more extensively than, all others.

.It is well recognized that the problems resented in the production of satisfactory detonator charges are quite different from those existing in the field of general explosives and that 'a parently slight changes in proportions an 'nzthe ingredients frequently produce surprising diflerences in result.

perfect what is commonly known as a compound detonator. A part of the fulminate charge is replaced by any one of a large number of .nitroaromatic compounds suitable for the purpose. The detonator is so In reoenti years efforts have been made to Application filed March 1, 1923. Serial No. 622,208.

constructed that the nitroaromatic com-' pound is its-elf initiated by the detonation of the fulminate charge which is commonly known as a priming charge. More recently priming charges containing heavy metal azides have been proposed.

In the field of commercial detonators it is universally agreed that the properly constructed compound detonator greatly exceeds the ordinary fulminate composition detonator in initiating efliciency. The general application of this type of detonator has been greatly restricted, however, due to greater manufacturing costs'as compared with ordinary fulminate composition detonators. Despite the substitution of a less costly material, i. e., a nitroaromatic c'ompoundfor a part of the fulminate charge, the ultimate costof detonators thus charged is ordinarily no less and is usually greater than that of ordinary fulminate compositlon detonators. This is due to the increased number of operations required for the socalled compound detonators and also to the added expense of specially constructed detonator shells which are usually required.

I have found that not only may oxygen carriers be mixed with primary, detonating explosives such as fulminate of mercury without impairing the efliciency thereof but a similar admixture may also be made with any of thesecondary nitroaromatic charges with equally gratifying results.

I have found that mixtures of tetra'nitroaniline or trinitrophenylmethylnitroamine, commonly known as tetryl and any suitable oxygen carrier have a deton ating oxygen and of sufficient stability to yield a composition that may be safely charged in detonators with other explosive ingredients. Examples of suitable oxygen carriers are ammonium perchlorate, potassium perchlorate and potassium chlorate. Ammonium chlorate and ferric oxide are examples of unsuitable oxygen carriers; ammonium chlorate because of its lack of stability, and ferric oxide because its oxygen content is too firmly fixed to enter into the explosive reaction.

Thus my inventionconstitutes a distinct advancement in the art'of initiating explo 2. A main charge consisting of 0.5 gram of amixture of equal parts of tetranitroaniline and potassium chlorate is charged and pressed into an ordinary detonator shell. This secondary charge is then initiated with any suitable priming charge.

This priming charge may be fulminate of mercury or avmixture of fulminate of mercury and a heavy metal azide or any other suitable composition.

While I have cited specific examples of nitroaromatic compounds I wish to have it understood that in so doing the scope of my invention is not restricted to these par ticular explosives. The spirit of my invention includes all nitroaromatic compounds which are suitable for detonator compositions, when used in any suitable proportions mlxed with oxygencarriers. It should also be understood that my invention is not limited teeny particulanoxygen carrying com pound but includes any/salt richv in oxygen which is suitable for the purpose in question. A

. Having described my invention, what I clalm is:

1. A compound detonator consisting of a main charge and a priming charge and wherein the main charge consists of a mixture of equal parts of tetranitroaniline and potassium chlorate and wherein the prim-.

mg charge consists of a mixture of fulmlnate ofmercury and a heavy metal azide.

2. A compound detonator comprising amain charge consisting of a nitroaromatic compound and an oxygen carrier, in oombination with a priming charge consisting of a mixture of a heavy metal azide and fulminateof mercury.

y In testimony whereof he afiixes his signature in the presence of two witnesses.

BENNETT GROTTA.

Witnesses RUSSELL M. 000K,

ALLAN F. KRAPF. 

